Two-part sole for footwear

ABSTRACT

A sole for an article of footwear including a first part having a bottom surface with a plurality of first protrusions increasing in thickness from a medial side to a lateral side, where each adjacent pair of the first protrusions define a first recess therebetween, and a second part having a top surface with a plurality of second protrusions increasing in thickness from a lateral side to a medial side, where each adjacent pair of the second protrusions define a second recess therebetween. When the first part and the second part are attached together, the plurality of first protrusions and recesses on the bottom surface of the first part matingly engage corresponding ones of the plurality of second protrusions and recesses on the top surface of the second part to form a midsole that deflects and absorbs impact forces resulting from multiple running conditions.

BACKGROUND

Walking, jogging and running are forms of bipedal motion that causevarying levels of stress on a person's legs and feet. As a result, shoemanufacturers add cushions and supports to shoes to provide comfort andto absorb impact forces generated by the repeated contact of a person'sfeet with the ground when performing these activities.

Shoes have different supports and support structures depending on thetype of activity. For example, walking shoes do not require as muchsupport as running shoes due to the fact that running generates greaterstress and impact on a person's legs and feet during running. Cushionsand supports in shoes are configured to relieve the impact stress on aperson's body resulting from different running conditions. Overpronationis a running condition where a foot rolls inwardly such that the inneror medial portion of the foot absorbs a majority of the impact stress.In contrast, underpronation occurs when the impact stress is mainly onthe outer or lateral portion of the foot where the foot does not rollinwardly. Both of these types of running conditions are corrected byproviding more cushioning and support to the shoes at the areas of thefoot that absorb a majority of the impact stress. Adding cushioning andsupports to shoes to account for different running conditions, increasesthe manufacturing cost of the shoes and ultimately increases the cost ofshoes for consumers. Also, users must purchase different shoes fordifferent bipedal motion activities and to overcome different runningconditions, which significantly increases the costs associated withthose activities.

SUMMARY

An article of footwear is provided that includes a two-part sole thatdivides and deflects impact forces due to bipedal motion and providessupport at both the medial and lateral sides of the article of footwearto reduce the effects of multiple running conditions such asoverpronation and underpronation.

In an embodiment, a sole for an article of footwear is provided thatincludes a first part having a bottom surface with a plurality of firstprotrusions increasing in thickness from a medial side to a lateralside, where each adjacent pair of the first protrusions define a firstrecess therebetween, and a second part having a top surface with aplurality of second protrusions increasing in thickness from a lateralside to a medial side, where each adjacent pair of the secondprotrusions defines a second recess therebetween. When the first part(firmer material) and the second part (softer material) are attachedtogether, the plurality of first protrusions and recesses on the bottomsurface of the first part matingly engage corresponding ones of theplurality of second protrusions and recesses on the top surface of thesecond part to form a sole that deflects and absorbs impact forcesresulting from multiple running conditions.

In another embodiment, an article of footwear is provided that includesan upper and a midsole attached to the upper, where the midsole includesa first part and a second part. The first part includes a top surfaceand a bottom surface where the bottom surface includes a plurality offirst protrusions increasing in thickness from a medial side to alateral side and each adjacent pair of the first protrusions define afirst recess therebetween. The second part includes a top surface and abottom surface, where the top surface includes a plurality of secondprotrusions increasing in thickness from a lateral side to a medial sideand each adjacent pair of the second protrusions define a second recesstherebetween. When the first part and the second part are attachedtogether, the plurality of first protrusions and recesses on the bottomsurface of the first part matingly engage corresponding ones of theplurality of second protrusions and recesses on the top surface of thesecond part. The bottom surface of the second part includes a pluralityof tread members or angled cleats, where a rear portion of each treadmember is taller or thicker than a front portion of the tread member.Each of the tread members is positioned directly adjacent to thethickest portion of one of the second protrusions to allow the treadmember to bend or push into the second protrusion upon impact with theground to absorb the shock generated by the impact.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view an article of footwear including thepresent two-part sole.

FIG. 2 is an elevation view of a lateral side of the article of footwearof FIG. 1.

FIG. 3 is an elevation view of a medial side of the article of footwearof FIG. 1.

FIG. 4 is an exploded perspective view of the two-part sole of FIG. 1.

FIG. 5 is a top view of the lower portion of the two-part sole of FIGS.2-4.

FIG. 6 is a bottom view of the top portion of the two-part sole of FIGS.2-4.

FIG. 7 is a bottom perspective view of the article of footwear of FIG.1.

FIG. 8 is a fragmentary, enlarged view of the article of footwear ofFIG. 1 where the lower part of the two-part sole is not pressed into theupper part.

FIG. 9 is a fragmentary, enlarged view of the article of footwear ofFIG. 1 where a portion of the lower part of the two-part sole is pressedinto the upper part.

DETAILED DESCRIPTION

The present footwear sole includes two mating parts that combine todivide, absorb and deflect shock from impact forces resulting frombipedal motion activities, such as walking, jogging and running, tosubstantially reduce the effect of impact forces caused by multiplerunning conditions.

Referring now to FIGS. 1-9, an article of footwear or shoe generallydesignated 10, includes an upper 12 attached to a sole 14 by stitching,adhesive or any suitable attachment method. The sole 14 includes anupper part, first part or midsole 16 and a lower part, a second part oroutsole 18, which is attached to the midsole by stitching, molding,adhesive or by any suitable attachment methods or combination ofattachment methods. The combination of the midsole 16 and outsole 18 ofthe present two-part sole 14 provides enhanced cushioning, support andstability to a wearer's feet as described below.

The upper part or midsole 16 has a top surface 20 and an opposing sideor bottom surface 22 where the first part is preferably made of ethylenevinyl acetate (EVA) and is formed to generally follow the shape of aperson's foot. The top surface 20 is generally flat and is attached tothe upper 12 by adhesive. It should be appreciated that any suitableattachment method may be used to attach the first part or midsole to theupper 12. The bottom surface 22 of the first part 20 includes aplurality of first triangular-shaped protrusions or supports 24 formedby angled surfaces 26 that increase in thickness from a medial side 28to a lateral side 30. It should be appreciated that the angled surfaces26 may be at any suitable angle relative to the bottom surface 22. Inthe illustrated embodiment, the first supports 24 are separated bycorresponding first triangular-shaped grooves or recesses 32. As shownin FIG. 6, the toe portion 34 and the heel portion 36 of first part 20are generally flat and do not include the first supports 28. Thus asshown in FIGS. 2 and 3, the thickness of the first supports 24, andthereby the first part 16, is greatest at the medial side 30 andgradually decreases in thickness to the lateral side 32 of the midsole.The EVA material of the first part 20 provides cushioning and support toa wearer's feet to lessen the impact stress absorbed by the wearer'sbody, and more particularly, their legs and feet, resulting from runningconditions such as overpronation and underpronation.

Referring now to FIG. 6, the bottom surface 22 of the first part 16 alsoincludes two longitudinal recesses 38 that are spaced from each otherand extend generally longitudinally between the toe portion 34 and theheel portion 36 of the midsole 16. Each of the longitudinal recesses 38extends through each of the first supports 24 and respectively followsthe contour of the medial and lateral sides 28, 30 of the midsole 16.

Referring now to FIGS. 4 and 5, the second part or outsole 18 is made ofa generally soft polyurethane (PU) which provides cushioning to awearer's feet. In the illustrated embodiment, the second part 18 is madeof a material having a density that is less than a density of the firstpart 16. It should be appreciated that the first and second parts mayhave the same density, different densities or any suitable densities. Asshown in FIGS. 2 and 3, the top surface 40 of the second part 18includes triangular-shaped second protrusions or supports 44 formed byangled surfaces 45 where the supports 44 are separated by correspondingtriangular-shaped second grooves or recesses 46. The second supports 44and the second grooves 46 align and mate with the corresponding firstprotrusions 24 and first recesses or grooves 32 on the bottom surface 22of the first part 16. As shown in FIG. 5, the second supports 44 and thesecond grooves 46 on the second part 18 are narrowest in thickness atthe medial side 28 and gradually increase in thickness to the lateralside 30. As a result, the second part 18 of the sole 14 provides morecushioning at the outer or lateral side 30 of the shoe to substantiallyreduce the impact forces on the wearer's feet at the lateral side of theshoe.

The second part 18 also includes two spaced, elongated longitudinalprotrusions or supports 48 that each extend generally longitudinallybetween the toe and heel portions 34, 36 as shown in FIG. 5. Theelongated supports 48 correspond in size and shape to the longitudinalrecesses 38 on the first part 16 of the sole 14 so that the longitudinalrecesses 38 and the longitudinal supports 48 matingly engage each otherwhen the first and second parts 16, 18 are attached together to form thesole 14. The combination of the longitudinal recesses 38 andlongitudinal supports 48 thereby provide additional structure andstability to the shoe.

To enhance traction with the ground, the second part 18 includes aplurality of tread members 50 that extend from the bottom surface 42 ofthe second part 18. Each of the tread members 50 has a generallytriangular shape with an angled front portion 52 and a generallystraight, rear portion 54. The angled front portion 52 of each treadmember 50 includes a plurality of steps or stepped surfaces 56. As shownFIGS. 1-3, the tread members 50 are positioned adjacent to the secondprotrusions 44 so that the rear portion 54 of each tread member 50generally aligns with the thickest or tallest portion of the secondprotrusions. It should be appreciated that the tread members 50 may bepositioned at any suitable location relative to the second protrusions44. In the heel portion 36 of the shoe 10, smaller tread members 58 arepositioned between the tread members 50 to enhance the traction of thebottom surface 42 of the outsole 18 with the ground. It should beappreciated that any suitable number of smaller tread members 58 may bepositioned between the tread members 50 and the tread members 50 and 58may have any suitable size and shape.

Referring now to FIGS. 2, 3, 8 and 9, as discussed above, the rearportions 54 of the tread members 50 on the bottom surface 42 of thesecond part or outsole 18 are positioned to be generally aligned withthe thickest or tallest portions of the second protrusions 44 on thelateral side 30 of the shoe (FIG. 2) and the thinnest or shortestportions of the second protrusions 44 on the medial side 28 of the shoe(FIG. 3). Accordingly, when one or more of the tread members 50 contactsthe ground, each impacted tread member is moved, pushed or forcedupwardly due to the impact with the ground. As shown in FIG. 9, theupward movement of each tread member 50 on the lateral side 30 of theshoe 10 causes the rear portion 54 of the tread member 50 to move intothe thickest or tallest portion of a corresponding second protrusion. Incontrast, the thinnest or shortest portions of second protrusions 44 arelocated on the medial side 28 of the shoe. As a result, there is less ofthe softer material forming the second protrusions 44 between the treadmembers 50 and the first part or midsole 16 on the medial side 28 of theshoe. The firmer first part or midsole 16 inhibits the upward movementof the tread members 50 on the medial side 28 of the shoe, whichprovides additional support and stability to the medial side of the shoewith less cushioning. It should be appreciated that the first part 16and the second part 18 may be made of any suitable materials orcombination of materials. It should also be appreciated that the firstand second parts may be made of materials having any suitable densities.

The first and second parts 16, 18 of the present sole 10 fit togethersuch that the first protrusions 24 of the first part 16 matingly engagethe corresponding second grooves 26 of the second part 18 and the secondprotrusions 44 of the second part 18 matingly engage the correspondingfirst recesses 32 of the first part 16. The combination of the first andsecond parts 16, 18 of the sole 14 provide firm support at the inner ormedial side 28 of a shoe to reduce the impact stresses fromoverpronation, and cushioning at the outer or lateral side 30 of theshoe for absorbing impact stresses due to underpronation. Further, thepresent sole 14 divides and deflects the shock generated by the impactforces so that less of the shock is transferred to a wearer's feet andlegs. Thus, the present two-part sole 14 allows for great traction andstability on soft surfaces while transitioning to substantial cushioningand support on firm surfaces. The present two-part sole 14 also requiresless parts, such as cushioning layers, than conventional shoes, whichreduces the complexity and the weight of the shoe while providingsupport and stability to wearers.

While a particular embodiment of the present article of footwear hasbeen described herein, it will be appreciated by those skilled in theart that changes and modifications may be made thereto without departingfrom the invention in its broader aspects.

What is claimed is:
 1. A sole for an article of footwear comprising: afirst part including a bottom surface having a plurality of firstprotrusions increasing in thickness from a medial side to a lateralside, each adjacent pair of said first protrusions defining a firstrecess therebetween; and a second part including a top surface having aplurality of second protrusions increasing in thickness from a lateralside to a medial side, each adjacent pair of said second protrusionsdefining a second recess therebetween, wherein when said first part andsaid second part are attached together, said plurality of firstprotrusions and recesses on said bottom surface of said first partmatingly engage corresponding ones of said plurality of secondprotrusions and recesses on said top surface of said second part.
 2. Thesole of claim 1, wherein said first protrusions have a triangular shape.3. The sole of claim 2, wherein said second protrusions have atriangular shape.
 4. The sole of claim 1, wherein said secondprotrusions have a triangular shape.
 5. The sole of claim 4, whereinsaid first protrusions have a triangular shape.
 6. The sole of claim 1,wherein each said first recess of said first part have a triangularshape and decrease in width from the medial side to lateral side.
 7. Thesole of claim 1, wherein each said recess of said second part have atriangular shape and decrease in width from the lateral side to medialside.
 8. The sole of claim 1, wherein said first part further comprisestwo longitudinal recesses extending between the toe and heel portions ofthe first part.
 9. The sole of claim 8, wherein said second part furthercomprises two longitudinal supports extending between the toe and heelportions of the second part, said longitudinal supports being configuredto matingly engage said two longitudinal protruding recesses of saidfirst part when said first and second parts are attached together. 10.The sole of claim 1, wherein said second part includes a plurality oftread members, each of said tread members being positioned adjacent to adifferent one of said second protrusions.
 11. An article of footwearcomprising: an upper; and a sole attached to said upper, said soleincluding a first part and a second part, said first part including atop surface and a bottom surface, said bottom surface including aplurality of first protrusions increasing in thickness from a medialside to a lateral side, each adjacent pair of said first protrusionsdefining a first recess therebetween, said second part including a topsurface and a bottom surface, said top surface including a plurality ofsecond protrusions increasing in thickness from a lateral side to amedial side, each adjacent pair of said second protrusions defining asecond recess therebetween, wherein when said first part and said secondpart are attached together, said plurality of first protrusions andrecesses on said bottom surface of said first part matingly engagecorresponding ones of said plurality of second protrusions and recesseson said top surface of said second part.
 12. The article of footwear ofclaim 11, wherein said first protrusions have a triangular shape. 13.The article of footwear of claim 12, wherein said second protrusionshave a triangular shape.
 14. The article of footwear of claim 11,wherein said second protrusions have a triangular shape.
 15. The articleof footwear of claim 14, wherein said first protrusions have atriangular shape.
 16. The article of footwear of claim 11, wherein saidrecesses of said first part have a triangular shape and decrease inwidth from the medial side to lateral side.
 17. The article of footwearof claim 11, wherein said recesses of said second part have a triangularshape and decrease in width from the lateral side to medial side. 18.The article of footwear of claim 11, wherein said first part furthercomprises two longitudinal recesses extending between the toe and heelportions of the first part.
 19. The article of footwear of claim 11,wherein said second part further comprises two longitudinal supportsextending between the toe and heel portions of the second part, saidlongitudinal supports being configured to matingly engage said twolongitudinal recesses of said first part when said first and secondparts are attached together.
 20. The sole of claim 11, wherein saidsecond part includes a plurality of tread members, each of said treadmembers being positioned adjacent to a different one of said secondprotrusions.